5-alarm fire raging at NJ industrial building

Firefighters are battling a five-alarm fire at a northern New Jersey industrial building that has extended to some adjoining buildings.

At least two firefighters have sustained injuries while battling the blaze, which broke out Sunday morning in Harrison. Their injuries are not believed to be serious.

It's not yet clear what sparked the blaze, which sent heavy, black smoke spewing from the two-story building in the Hudson County community. Witnesses also reported hearing an explosion shortly after firefighters arrived.